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Tor Hervig

Publications and source records attributed to Tor Hervig.

8 recordsLinked to original sources
PubMed2006

A novel HPLC method for the measurement of thiobarbituric acid reactive substances (TBARS). A comparison with a commercially available kit.

OBJECTIVES: Malondialdehyde (MDA) as a part of thiobarbituric acid reacting substances (TBARS) is frequently used as an indicator of lipid peroxidation. Most methods for the measurement of TBARS require long derivatization time and addition of antioxidants in the samples. Furthermore, comparison of these methods with commercially available HPLC kits is lacking. DESIGN AND METHODS: We investigated column performance of five different columns, tested eight different acids for the hydrolysis of the samples, and estimated stability of derivatized plasma samples with different anticoagulants. The samples were derivatized with TBA. The peak for the TBA(2)-MDA adduct was separated and detected by HPLC. RESULTS: Performance of the Phenomenex Gemini column was best. PCA at the concentration of 0.1125 N was used in this method. Coefficient of variation (CV %) within the run and between the run was 4.1% and 6.7%, and analytical recovery was 90-94%. The retention time of the TBA(2)-MDA peak was 1.8 min. Reference intervals for TBARS in serum from 250 individuals were 0.53 and 2.1 micromol/l using our HPLC method and 0.07 and 0.24 micromol/l using the Chromsystems assay. Linear regression with log converted values revealed weak relationship between the two methods (r(2) = 0.064). CONCLUSIONS: Our HPLC method for the analysis of TBARS in serum and plasma is fast and accurate and therefore can be used in clinical studies.

Adolescent↗
PubMed2005

Evaluation of a porcine model to study in vivo platelet activation.

INTRODUCTION: In order to investigate if decompression sickness involves platelet activation an animal model was evaluated. MATERIALS AND METHODS: Twenty-four thiopentone-midazolam-fentanyl-anaesthetized pigs in four groups received 5-min infusions of adenosine diphosphate (25 mg/kg) or platelet activating factor (0.4 microg/kg). Groups 1 and 2 (adenosine diphosphate, n=6 and platelet activating factor, n=6) were studied for 30 min and then sacrificed. Groups 3 and 4 (adenosine diphosphate, n=6 and platelet activating factor, n=6) were sacrificed immediately afterwards to study short-term changes. Haemodynamics, platelet counts and post mortem lung platelet aggregates were registered. Groups 1 and 2 also had indium platelet labelling, lung scintigraphy and platelet accumulation index calculations performed. RESULTS: Adenosine diphosphate induced immediate and more profound transient shocks. Platelet and leukocyte count decreases and occurrences of post mortem lung platelet aggregates were significantly more profound in the 5-min adenosine diphosphate group (Group 3) than in the platelet activating factor group (Group 4). With platelet labelling there were positive platelet accumulation index trends in the 30-min adenosine diphosphate group (Group 1). Adenosine diphosphate also produced platelet aggregation in platelet-rich porcine plasma. Only adenosine diphosphate (an intermediate platelet agonist) showed signs of platelet activation when considering all platelet parameters. The model should be further evaluated with different bolus doses of adenosine diphosphate, but may be used to evaluate if gas bubbles introduced into the circulation (as with decompression sickness), or possibly if clinical drugs, might produce platelet activation in vivo.

Animals↗
PubMed2004

[Blood transfusion and pretransfusion testing in patients with warm autoimmune haemolytic anaemia].

BACKGROUND: In warm autoimmune haemolytic anaemia, patients have red cell autoantibodies that complicate the serological compatibility testing before transfusion. Different autoadsorption techniques are utilised for more extensive pretransfusion testing. We reviewed the literature on blood transfusion in these patients. We also present our experience with autoadsorption by papain and polyethylene glycol methods. MATERIAL AND METHODS: Blood samples from 13 patients with warm autoantibodies were analysed in parallel. After autoadsorption, antibody screening and identification tests were performed to detect possible red cell alloantibodies. If the serological testing is inadequate, clinically important alloantibodies can be ignored before transfusion, which can lead to haemolytic transfusion reactions. RESULTS: Autoantibodies were completely adsorbed in six of the 13 patients. In five, alloantibodies were detected. In three patients, different results were obtained with the two different techniques. INTERPRETATION: Restrictive transfusion practice in warm autoimmune haemolytic anaemia is recommended. Adequate pretransfusion testing in a specialised laboratory is required before transfusion. Autoadsorption with polyethylene glycol and papain can supplement each other in pretransfusion testing.

Adsorption↗
PubMed2004

Guidelines for transfusion in Norway.

The Norwegian guidelines for transfusion are harmonised in terms of standards with the European directives, but we have two areas where there are substantial differences. First, in Norway a blood donor is defined as a patient in legal terms. Secondly, we have stricter criteria for geographical origin of the people who are allowed to donate blood than most other countries. It is a challenge to provide information stating that these guidelines are related to the risk of transmitting infectious disease rather than discrimination. Increased focus on hemovigilance and closer contact between the blood banks and the national health authorities will be major issues in future work to improve the quality of Transfusion Medicine in Norway.

Blood Donors↗
PubMed2003

[Thrombocytopaenia in pregnancy].

BACKGROUND, MATERIAL AND METHODS: This paper provides a short review of thrombocytopaenia in pregnancy based on a search in PubMed as well as clinical experience. RESULTS AND INTERPRETATION: Normal platelet count in pregnancy is 250-290 x 10(9)/l, Thrombocytopaenia in pregnancy may be defined as platelet counts below 150 x 10(9)/l. Benign gestational thrombocytopaenia (platelet count 70-150 x 10(9)/l without clinical findings or any maternal or fetal risk) develops in 5%-12% of all pregnancies in the third trimester. Immune thrombocytopaenia (ITP) occurs in about one or two out of 1000 pregnancies and may be complicated by fetal alloimmune thrombocytopaenia. Thrombocytopaenia is present in nearly half of the cases with preeclampsia. The HELLP syndrome (Haemolysis, Elevated Liver enzymes and Low Platelet count) is classified according to platelet counts. Thrombotic thrombocytopenic purpura (TTP), haemolytic uremic syndrome (HUS) and fatty liver may imply low platelet counts. Infections, folate deficiency, leukaemia, congenital conditions, drugs or concurrent autoimmune disease may cause thrombocytopaenia. Platelet counts during pregnancy should be based on clinical indications.

Autoimmune Diseases↗
PubMed2003

A Y chromosome census of the British Isles.

The degree of population replacement in the British Isles associated with cultural changes has been extensively debated. Recent work has demonstrated that comparisons of genetic variation in the British Isles and on the European Continent can illuminate specific demographic processes in the history of the British Isles. For example, Wilson et al. used the similarity of Basque and Celtic Y chromosomes to argue for genetic continuity from the Upper Palaeolithic to the present in the paternal history of these populations (see also ). Differences in the Y chromosome composition of these groups also suggested genetic signatures of Norwegian influence in the Orkney Islands north of the Scottish mainland, an important center of Viking activities between 800 and 1300 A.D. More recently, Weale et al. argued for substantial Anglo-Saxon male migration into central England based on the analysis of eight British sample sets collected on an east-west transect across England and Wales. To provide a more complete assessment of the paternal genetic history of the British Isles, we have compared the Y chromosome composition of multiple geographically distant British sample sets with collections from Norway (two sites), Denmark, and Germany and with collections from central Ireland, representing, respectively, the putative invading and the indigenous populations. By analyzing 1772 Y chromosomes from 25 predominantly small urban locations, we found that different parts of the British Isles have sharply different paternal histories; the degree of population replacement and genetic continuity shows systematic variation across the sampled areas.

Chromosomes, Human, Y↗
PubMed2002

Effects of cytarabine and various anthracyclins on platelet activation: characterization of in vitro effects and their possible clinical relevance in acute myelogenous leukemia.

Previous in vitro studies have demonstrated that normal platelets and platelet-released mediators can alter in vitro characteristics of human acute myelogenous leukemia (AML) blasts. To further investigate whether platelets can be expected to adhere to and thereby affect AML blasts through their release of soluble mediators into a common microenvironment, we investigated (i) the effects on platelet activation by cytotoxic drugs commonly used in AML therapy; (ii) the occurrence of circulating activated platelets in acute leukemia patients; and (iii) the in vivo and in vitro adherence of platelets to AML blasts. The anthracyclins daunorubicin and idarubicin increased the expression of activation-associated membrane molecules (GPIIb/IIIa, CD62P, CD63) by normal platelets, daunorubicin then having the strongest effect. In contrast, cytarabine, epirubicin, doxorubicin and mitoxantrone had no significant effects. Although AML patients did not show increased levels of activated platelets in the circulation, adhesion of platelets to AML blasts was demonstrated both in vivo and in vitro. These results suggest that platelets and AML blasts may locate to common in vivo microenvironments, and platelet-derived soluble mediators may thereby affect the functional characteristics of the leukemia cells.

Adult↗